Confined and deconfined chaos in classical spin systems

Fuente: arXiv
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Autores principales: Kim, Hyeongjin, Schäfer, Robin, Long, David M., Polkovnikov, Anatoli, Chandran, Anushya
Formato: Preprint
Publicado: 2025
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author Kim, Hyeongjin
Schäfer, Robin
Long, David M.
Polkovnikov, Anatoli
Chandran, Anushya
author_facet Kim, Hyeongjin
Schäfer, Robin
Long, David M.
Polkovnikov, Anatoli
Chandran, Anushya
contents Weakly perturbed integrable many-body systems are typically chaotic, and thermal at late times. However, there are distinct relationships between the timescales for thermalization and chaos. The typical relationship is confined chaos: when trajectories are still confined to regions in phase space with constant conserved quantities (actions), the conjugate angle variables are already unstable. Chaotic instabilities thus far precede thermalization. In a different relationship, which we term deconfined chaos, chaotic instabilities and thermalization occur on the same timescale. We investigate these two qualitatively distinct scenarios through numerical and analytical studies of two perturbed integrable classical spin models: the Ishimori spin chain (confined chaos), and the central spin model with XX interactions (deconfined chaos). We analytically establish (super)-integrability in the latter model in a microcanonical shell. Deconfined chaos emerges through the separation of phase space into large quasi-integrable regions and a thin chaotic manifold. The latter leads to chaos and thermalization on the fastest possible timescale, which is proportional to the inverse perturbation strength. This behavior is reminiscent of the quantum SYK models and strange metals.
format Preprint
id arxiv_https___arxiv_org_abs_2507_07168
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Confined and deconfined chaos in classical spin systems
Kim, Hyeongjin
Schäfer, Robin
Long, David M.
Polkovnikov, Anatoli
Chandran, Anushya
Statistical Mechanics
Chaotic Dynamics
Exactly Solvable and Integrable Systems
Weakly perturbed integrable many-body systems are typically chaotic, and thermal at late times. However, there are distinct relationships between the timescales for thermalization and chaos. The typical relationship is confined chaos: when trajectories are still confined to regions in phase space with constant conserved quantities (actions), the conjugate angle variables are already unstable. Chaotic instabilities thus far precede thermalization. In a different relationship, which we term deconfined chaos, chaotic instabilities and thermalization occur on the same timescale. We investigate these two qualitatively distinct scenarios through numerical and analytical studies of two perturbed integrable classical spin models: the Ishimori spin chain (confined chaos), and the central spin model with XX interactions (deconfined chaos). We analytically establish (super)-integrability in the latter model in a microcanonical shell. Deconfined chaos emerges through the separation of phase space into large quasi-integrable regions and a thin chaotic manifold. The latter leads to chaos and thermalization on the fastest possible timescale, which is proportional to the inverse perturbation strength. This behavior is reminiscent of the quantum SYK models and strange metals.
title Confined and deconfined chaos in classical spin systems
topic Statistical Mechanics
Chaotic Dynamics
Exactly Solvable and Integrable Systems
url https://arxiv.org/abs/2507.07168